Since they have high performance, synthetic fibers such as nylon and polyester fibers have been used widely for clothing and in industrial areas. Fibrous sheets composed of nylons and polyesters are used frequently as three-dimensional products such as interlining cloths for clothes, brassieres, and pads for breasts and shoulders. Furthermore, recently, it has been the practice to stabilize the shape of the shirts composed of blended yarns consisting of a polyester and cotton.
On the one hand, nylons are very poor in dimensional stability in dry and wet conditions because hey expand when absorbing water, and contract when dried, and cannot be used in areas where dimensional stability is important. So, in recent years, as fibers for clothes, nylon fibers are mostly being replaced by polyesters.
On the other hand, polyesters are disadvantageously weak in resilient elasticity and liable to yield to repeated bending, even though good in dimensional stability in dry and wet conditions. For this reason, even though they are lower in cost than nylon 6 and nylon 66, they are little used for such applications as toothbrushes, artificial lawns, carpets, etc.
Japanese Laid-Open Patent Application (Kokai) No. 2-289101 (1990) discloses an interlining cloth using conjugate fibers having spiral crimps. Japanese Laid-Open Patent Application (Kokai) No. 3-130434 (1991) discloses an interlining cloth formed by a knitted/woven fabric using yarns having loops and fluffs. Japanese Laid-Open Patent Application (Kokai) No. 3-152203 (1991) discloses a bonded interlining cloth using crimped yarns.
However, the conventional polyester fibers are poor in resiliency, and for such applications as interlining cloths where good resiliency is required, they must be, for example, used in conjugation with highly resilient animal hair such as horse hair or human hair. Furthermore, since interlining cloths higher in resiliency can be less adapted to the forms of clothing, then disadvantageously a sophisticated sewing technique is required.